net.sf.saxon.value

## Class DateValue

- java.lang.Object
- - net.sf.saxon.om.AbstractItem
  - - net.sf.saxon.value.AtomicValue
    - - net.sf.saxon.value.CalendarValue
      - - net.sf.saxon.value.GDateValue
        - - net.sf.saxon.value.DateValue

- All Implemented Interfaces:
    Comparable, PullEvent, AtomicSequence, GroundedValue, IdentityComparable, Item, Sequence, ConversionResult

      public class DateValue
      extends GDateValue
      implements Comparable

  A value of type Date. Note that a Date may include a TimeZone.

- - ### Field Summary

    - ### Fields inherited from class net.sf.saxon.value.GDateValue

      `day, daysPerMonth, month, monthData, xsd10rules, year`

    - ### Fields inherited from class net.sf.saxon.value.CalendarValue

      `NO_TIMEZONE`

    - ### Fields inherited from class net.sf.saxon.value.AtomicValue

      `typeLabel`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `DateValue(CharSequence s)` Constructor: create a date value from a supplied string, in ISO 8601 format
    `DateValue(CharSequence s, ConversionRules rules)` Constructor: create a date value from a supplied string, in ISO 8601 format
    `DateValue(GregorianCalendar calendar, int tz)` Create a DateValue
    `DateValue(int year, byte month, byte day)` Constructor given a year, month, and day.
    `DateValue(int year, byte month, byte day, boolean xsd10)` Constructor given a year, month, day and xsd10.
    `DateValue(int year, byte month, byte day, int tz, AtomicType type)` Constructor given a year, month, and day, and timezone, and an AtomicType representing a subtype of xs:date.
    `DateValue(int year, byte month, byte day, int tz, boolean xsd10)` Constructor given a year, month, and day, and timezone.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `CalendarValue` | `add(DurationValue duration)` Add a duration to a date
    `CalendarValue` | `adjustTimezone(int timezone)` Return a new date with the same normalized value, but in a different timezone.
    `int` | `compareTo(Object v2)` Context-free comparison of two DateValue values.
    `AtomicValue` | `copyAsSubType(AtomicType typeLabel)` Make a copy of this date value, but with a new type label
    `static DateValue` | `dateFromJulianDayNumber(int julianDayNumber)` Get the Gregorian date corresponding to a particular Julian day number.
    `CharSequence` | `getCanonicalLexicalRepresentation()` Get the canonical lexical representation as defined in XML Schema.
    `static int` | `getDayOfWeek(int year, int month, int day)` Get the day of the week.
    `static int` | `getDayWithinYear(int year, int month, int day)` Get the ordinal day number within the year (1 Jan = 1, 1 Feb = 32, etc)
    `int` | `getJulianDayNumber()` Calculate the Julian day number at 00:00 on this date.
    `static int` | `getJulianDayNumber(int year, int month, int day)` Calculate the Julian day number at 00:00 on a given date.
    `CharSequence` | `getPrimitiveStringValue()` Convert to string
    `BuiltInAtomicType` | `getPrimitiveType()` Determine the primitive type of the value.
    `static int` | `getWeekNumber(int year, int month, int day)` Get the ISO week number for a given date.
    `static int` | `getWeekNumberWithinMonth(int year, int month, int day)` Get the week number within a month.
    `static ConversionResult` | `makeDateValue(CharSequence in, ConversionRules rules)` Static factory method: construct a DateValue from a string in the lexical form of a date, returning a ValidationFailure if the supplied string is invalid
    `DayTimeDurationValue` | `subtract(CalendarValue other, XPathContext context)` Determine the difference between two points in time, as a duration
    `static DateValue` | `tomorrow(int year, byte month, byte day)` Get the date that immediately follows a given date
    `static DateValue` | `yesterday(int year, byte month, byte day)` Get the date that immediately precedes a given date

    - ### Methods inherited from class net.sf.saxon.value.GDateValue

      `compareTo, equals, getCalendar, getComparisonKey, getComponent, getDay, getMonth, getSchemaComparable, getYear, hashCode, isLeapYear, isValidDate, setLexicalValue, toDateTime`

    - ### Methods inherited from class net.sf.saxon.value.CalendarValue

      `adjustTimezone, appendTimezone, appendTimezone, getTimezoneInMinutes, getXPathComparable, hasTimezone, isIdentical, makeCalendarValue, removeTimezone, setTimezoneInMinutes`

    - ### Methods inherited from class net.sf.saxon.value.AtomicValue

      `asAtomic, checkPermittedContents, effectiveBooleanValue, getCardinality, getItemType, getStringValue, getStringValueCS, head, isIdentical, isNaN, itemAt, iterate, process, setTypeLabel, toString`

    - ### Methods inherited from class net.sf.saxon.om.AbstractItem

      `getLength, reduce, subsequence`

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

    - ### Methods inherited from interface net.sf.saxon.om.AtomicSequence

      `getLength`

    - ### Methods inherited from interface net.sf.saxon.om.GroundedValue

      `reduce, subsequence`

- - ### Constructor Detail

    - #### DateValue

          public DateValue(int year,
                   byte month,
                   byte day)

      Constructor given a year, month, and day. Performs no validation.
      Parameters:
        `year` - The year as held internally (note that the year before 1AD is supplied as 0, but will be displayed on output as -0001)
        `month` - The month, 1-12
        `day` - The day, 1-31

    - #### DateValue

          public DateValue(int year,
                   byte month,
                   byte day,
                   boolean xsd10)

      Constructor given a year, month, day and xsd10. Performs no validation.
      Parameters:
        `year` - The year as held internally (note that the year before 1AD is supplied as 0)
        `month` - The month, 1-12
        `day` - The day, 1-31
        `xsd10` - Schema version flag. If set to true, the year before 1AD is displayed as -0001; if false, it is displayed as 0000; but in both cases, it is held internally as zero. The flag makes no difference to dates later than 1AD.

    - #### DateValue

          public DateValue(int year,
                   byte month,
                   byte day,
                   int tz,
                   boolean xsd10)

      Constructor given a year, month, and day, and timezone. Performs no validation.
      Parameters:
        `year` - The year as held internally (note that the year before 1AD is 0)
        `month` - The month, 1-12
        `day` - The day, 1-31
        `tz` - the timezone displacement in minutes from UTC. Supply the value `CalendarValue.NO_TIMEZONE` if there is no timezone component.
        `xsd10` - Schema version flag. If set to true, the year before 1AD is displayed as -0001; if false, it is displayed as 0000; but in both cases, it is held internally as zero. The flag makes no difference to dates later than 1AD.

    - #### DateValue

          public DateValue(int year,
                   byte month,
                   byte day,
                   int tz,
                   AtomicType type)

      Constructor given a year, month, and day, and timezone, and an AtomicType representing a subtype of xs:date. Performs no validation.
      Parameters:
        `year` - The year as held internally (note that the year before 1AD is 0)
        `month` - The month, 1-12
        `day` - The day 1-31
        `tz` - the timezone displacement in minutes from UTC. Supply the value `CalendarValue.NO_TIMEZONE` if there is no timezone component.
        `type` - the type. This must be a type derived from xs:date, and the value must conform to this type. The method does not check these conditions.

    - #### DateValue

          public DateValue(CharSequence s)
                    throws ValidationException

      Constructor: create a date value from a supplied string, in ISO 8601 format
      Parameters:
        `s` - the lexical form of the date value. Currently this assumes XSD 1.0 conventions for BC years (that is, no year zero), but this may change at some time.
      Throws:
        `ValidationException` - if the supplied string is not a valid date

    - #### DateValue

          public DateValue(CharSequence s,
                   ConversionRules rules)
                    throws ValidationException

      Constructor: create a date value from a supplied string, in ISO 8601 format
      Parameters:
        `s` - the lexical form of the date value
        `rules` - the conversion rules (determining whether year zero is allowed)
      Throws:
        `ValidationException` - if the supplied string is not a valid date

    - #### DateValue

          public DateValue(GregorianCalendar calendar,
                   int tz)

      Create a DateValue
      Parameters:
        `calendar` - the absolute date/time value
        `tz` - The timezone offset from GMT in minutes, positive or negative; or the special value NO_TIMEZONE indicating that the value is not in a timezone

  - ### Method Detail

    - #### makeDateValue

          public static ConversionResult makeDateValue(CharSequence in,
                                       ConversionRules rules)

      Static factory method: construct a DateValue from a string in the lexical form of a date, returning a ValidationFailure if the supplied string is invalid
      Parameters:
        `in` - the lexical form of the date
        `rules` -
      Returns:
        either a DateValue or a ValidationFailure

    - #### getPrimitiveType

          public BuiltInAtomicType getPrimitiveType()

      Determine the primitive type of the value. This delivers the same answer as getItemType().getPrimitiveItemType(). The primitive types are the 19 primitive types of XML Schema, plus xs:integer, xs:dayTimeDuration and xs:yearMonthDuration, and xs:untypedAtomic. For external objects, the result is AnyAtomicType.
      Specified by:
        `getPrimitiveType` in class `AtomicValue`
      Returns:
        the primitive type

    - #### tomorrow

          public static DateValue tomorrow(int year,
                           byte month,
                           byte day)

      Get the date that immediately follows a given date
      Parameters:
        `year` - the year
        `month` - the month (1-12)
        `day` - the day (1-31)
      Returns:
        a new DateValue with no timezone information

    - #### yesterday

          public static DateValue yesterday(int year,
                            byte month,
                            byte day)

      Get the date that immediately precedes a given date
      Parameters:
        `year` - the year
        `month` - the month (1-12)
        `day` - the day (1-31)
      Returns:
        a new DateValue with no timezone information

    - #### getPrimitiveStringValue

          public CharSequence getPrimitiveStringValue()

      Convert to string
      Specified by:
        `getPrimitiveStringValue` in class `AtomicValue`
      Returns:
        ISO 8601 representation.

    - #### getCanonicalLexicalRepresentation

          public CharSequence getCanonicalLexicalRepresentation()

      Get the canonical lexical representation as defined in XML Schema. This is not always the same as the result of casting to a string according to the XPath rules. For xs:date, the timezone is adjusted to be in the range +12:00 to -11:59
      Specified by:
        `getCanonicalLexicalRepresentation` in interface `AtomicSequence`
      Overrides:
        `getCanonicalLexicalRepresentation` in class `AtomicValue`
      Returns:
        the canonical lexical representation if defined in XML Schema; otherwise, the result of casting to string according to the XPath 2.0 rules

    - #### copyAsSubType

          public AtomicValue copyAsSubType(AtomicType typeLabel)

      Make a copy of this date value, but with a new type label
      Specified by:
        `copyAsSubType` in class `AtomicValue`
      Parameters:
        `typeLabel` - the new type label: must be a subtype of xs:date
      Returns:
        the new xs:date value

    - #### adjustTimezone

          public CalendarValue adjustTimezone(int timezone)

      Return a new date with the same normalized value, but in a different timezone. This is called only for a DateValue that has an explicit timezone
      Specified by:
        `adjustTimezone` in class `CalendarValue`
      Parameters:
        `timezone` - the new timezone offset, in minutes
      Returns:
        the time in the new timezone. This will be a new TimeValue unless no change was required to the original value

    - #### add

          public CalendarValue add(DurationValue duration)
                            throws XPathException

      Add a duration to a date
      Specified by:
        `add` in class `CalendarValue`
      Parameters:
        `duration` - the duration to be added (may be negative)
      Returns:
        the new date
      Throws:
        `XPathException` - if the duration is an xs:duration, as distinct from a subclass thereof

    - #### subtract

          public DayTimeDurationValue subtract(CalendarValue other,
                                      XPathContext context)
                                        throws XPathException

      Determine the difference between two points in time, as a duration
      Overrides:
        `subtract` in class `CalendarValue`
      Parameters:
        `other` - the other point in time
        `context` - the XPath dynamic context. May be set to null only if both values contain an explicit timezone, or if neither does so.
      Returns:
        the duration as an xs:dayTimeDuration
      Throws:
        `XPathException` - for example if one value is a date and the other is a time

    - #### compareTo

          public int compareTo(Object v2)

      Context-free comparison of two DateValue values. For this to work, the two values must either both have a timezone or both have none.
      Specified by:
        `compareTo` in interface `Comparable`
      Parameters:
        `v2` - the other value
      Returns:
        the result of the comparison: -1 if the first is earlier, 0 if they are equal, +1 if the first is later
      Throws:
        `ClassCastException` - if the values are not comparable (which might be because no timezone is available)

    - #### getJulianDayNumber

          public static int getJulianDayNumber(int year,
                               int month,
                               int day)

      Calculate the Julian day number at 00:00 on a given date. This algorithm is taken from http://vsg.cape.com/~pbaum/date/jdalg.htm and http://vsg.cape.com/~pbaum/date/jdalg2.htm (adjusted to handle BC dates correctly)

      Note that this assumes dates in the proleptic Gregorian calendar

      Parameters:
        `year` - the year
        `month` - the month (1-12)
        `day` - the day (1-31)
      Returns:
        the Julian day number

    - #### getJulianDayNumber

          public int getJulianDayNumber()

      Calculate the Julian day number at 00:00 on this date.

      Note that this assumes dates in the proleptic Gregorian calendar

      Returns:
        the Julian day number

    - #### dateFromJulianDayNumber

          public static DateValue dateFromJulianDayNumber(int julianDayNumber)

      Get the Gregorian date corresponding to a particular Julian day number. The algorithm is taken from http://www.hermetic.ch/cal_stud/jdn.htm#comp
      Parameters:
        `julianDayNumber` - the Julian day number
      Returns:
        a DateValue with no timezone information set

    - #### getDayWithinYear

          public static int getDayWithinYear(int year,
                             int month,
                             int day)

      Get the ordinal day number within the year (1 Jan = 1, 1 Feb = 32, etc)
      Parameters:
        `year` - the year
        `month` - the month (1-12)
        `day` - the day (1-31)
      Returns:
        the ordinal day number within the year

    - #### getDayOfWeek

          public static int getDayOfWeek(int year,
                         int month,
                         int day)

      Get the day of the week. The days of the week are numbered from 1 (Monday) to 7 (Sunday)
      Parameters:
        `year` - the year
        `month` - the month (1-12)
        `day` - the day (1-31)
      Returns:
        the day of the week, 1=Monday .... 7=Sunday

    - #### getWeekNumber

          public static int getWeekNumber(int year,
                          int month,
                          int day)

      Get the ISO week number for a given date. The days of the week are numbered from 1 (Monday) to 7 (Sunday), and week 1 in any calendar year is the week (from Monday to Sunday) that includes the first Thursday of that year
      Parameters:
        `year` - the year
        `month` - the month (1-12)
        `day` - the day (1-31)
      Returns:
        the ISO week number

    - #### getWeekNumberWithinMonth

          public static int getWeekNumberWithinMonth(int year,
                                     int month,
                                     int day)

      Get the week number within a month. This is required for the XSLT format-date() function. The days of the week are numbered from 1 (Monday) to 7 (Sunday), and week 1 in any calendar month is the week (from Monday to Sunday) that includes the first Thursday of that month.

      See bug 21370 which clarified the specification. This caused a change to the Saxon implementation such that the days before the start of week 1 go in week 5, not week zero.

      Parameters:
        `year` - the year
        `month` - the month (1-12)
        `day` - the day (1-31)
      Returns:
        the week number within a month

Copyright (c) 2004-2013 Saxonica Limited. All rights reserved.